Vlasov simulation of laser-driven shock acceleration and ion turbulence

TL;DR

This paper uses Vlasov simulations to study laser-driven ion shocks and turbulence in overdense plasma, revealing ion reflection due to turbulence driven by relativistic electron bunches, and introduces a charge-conserving numerical method.

Contribution

It presents a novel Vlasov simulation approach with a correction for charge conservation in relativistic regimes, providing insights into ion turbulence and shock dynamics.

Findings

Ion distribution affected by turbulence from relativistic electron bunches

Onset of ion reflection at shock front in cold plasma

Analytic model for turbulence driven by electron-ion coupling

Abstract

We present a Vlasov, i.e. a kinetic Eulerian simulation study of nonlinear collisionless ion-acoustic shocks and solitons excited by an intense laser interacting with an overdense plasma. The use of the Vlasov code avoids problems with low particle statistics and allows a validation of particle-in-cell results. A simple original correction to the splitting method for the numerical integration of the Vlasov equation has been implemented in order to ensure the charge conservation in the relativistic regime. We show that the ion distribution is affected by the development of a turbulence driven by the relativistic "fast" electron bunches generated at the laser-plasma interaction surface. This leads to the onset of ion reflection at the shock front in an initially cold plasma where only soliton solutions without ion reflection are expected to propagate. We give a simple analytic model to describe the onset of the turbulence as a nonlinear coupling of the ion density with the fast electron currents, taking the pulsed nature of the relativistic electron bunches into account.